Treatment, storage and reprocessing of waste from nuclear power plants are substantial concerns associated with nuclear power plants. The present state of the art for dry head-end reprocessing of commercial spent nuclear fuel is complex, expensive, and subject to discharge of radioactive gases into the environment. Reprocessing methodologies currently include the following main steps (batch and semi-continuous):
(i) chopping of the fuel bundles;
(ii) loading of the chopped pieces into a concentrated nitric acid dissolver;
(iii) prolonged acid digestion/dissolution and off-gas treatment;
(iv) removal of the metallic cladding and hardware pieces;
(v) filtering of the solution to remove undissolved solids;
(vi) multiple solvent extractions of the acid solution using a series of extractants; and
(vii) drying/calcinations of the separated products, acid recovery, and conversion of the remaining solution containing the fission products and minor actinide elements to a vitrified waste form.
The major challenges with existing reprocessing technology are the complexity and environmental risks; therefore, there is substantial room for improvement over the current state of the art.